This is is a great question. But not a very simple one to answer. It’s actually been a topic of discussion a number of times recently here with the founders.
Let me see if I can give a good summary...
Firstly, since the Netlify platform (the hosting platform and the build infrastructure) is built to sit across as many as 7 different cloud hosting providers (including those you mentioned above) and gracefully balance across them, it is difficult to give very specific details about the exact service on which Netlify sits and the resultant carbon offsetting in place. As you mention, many of those cloud providers give some level of carbon offsetting themselves, but they each differ, as does our usage across them, so good data is tricky here.
However...
We care a lot about this issue too, and have been exploring the possibilities for doing real, effective carbon offsetting not just for our hosting infrastructure, but also for other aspects of our operations like long haul travel etc.
There are lots of schemes which allow payments to be made towards carbon offsetting. But our research has not shown that these are often as effective as we’d like. We don’t want to just pay a fee and feel better. We would prefer to make a substantive effort to truly offset. We are exploring a number of possible options for this at present, but I can’t currently give a more definitive answer than that, I’m sorry to say. Our investigation into this is ongoing.
One other thought...
I need data data to back this next statement up, and perhaps this is something we might put some research into at some point, but the model of building a site only when it’s code or content changes, and then serving the static assets which result from that build should be far more energy efficient than serving a site with a traditional model. Particularly at scale and under load, the JAMstack model where static assets are served should require far less ‘work’ than having a dynamic back end which must scale to perform more and more logical operations as load increases.
I hope we’ll be able to give more information about all of this in future.